Icahn seems to be referring to the past eight years under Barack Obama, a time when the government mandated health care coverage for all Americans and also put in place many reforms for Wall Street and big banks.

Icahn was named an adviser to the Trump administration last month, with a specific focus on undoing or softening some of the rules put in place during the Obama administration.

The Trump team said Icahn would help "American entrepreneurs shed job-killing regulations that stifle economic growth."

The Dow soared about 140% during Obama's eight years in office. After bottoming out in March 2009, the market roared back from the depths of the 2008 financial crisis and Great Recession and is now trading near record high levels.

Many experts say that Obama's policies deserve some, albeit not all, of the credit. Low interest rates from the Federal Reserve and innovation from tech giants Apple(AAPL), Google(GOOGL), Facebook(FB) and others in Silicon Valley also helped fuel the market's surge.

Still, some on Twitter defended Icahn and Trump. @jdcaetano wrote that "8 years of Democratic socialism should never have been inflicted on us! Let's move onward and upward."

Investors initially greeted Trump's win as a positive sign too. Shares of Icahn's own publicly traded firm Icahn Enterprises(IEP) have surged since Trump won the election, along with the broader market.

But the market has pulled back in recent weeks due to concerns that Trump's isolationist policies could actually be detrimental to Corporate America. Icahn Enterprises is down more than 2% as well.

And Icahn even conceded in an interview with CNN's Poppy Harlow last month that he thought the market rally following Trump's win was "a little overdone."